If you're curious about thee state of #FediE2EE.
I've been implementing the cryptography protocols used in building Key Transparency for Fedi.
https://github.com/fedi-e2ee/pkd-crypto
With this in hand, I'm writing a reference implementation of the server software as defined in the specification.
https://github.com/fedi-e2ee/public-key-directory-specification
Once this is implemented, I'm going to update the specification with anything I learned while writing the server osftware.
One thing I already learned: I need to be specific about how HPKE ciphertexts are serialized. The current spec draft doesn't tell implementors what to do here.
Once the spec + implementation are in a good place, I'll deploy a test instance and release a PHP client (using the same crypto library).
Separately, a Rust client is being developed. https://github.com/Waelwindows/pkd-client
The main idea here is to FFI the Rust implementation in other languages (Ruby, etc.).
Once all this is done, we get to go through a few cycles of peer review until we calcify the spec with a major version 1.0 release